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Waikiki Beach Walk - Retail Waikiki Beach Walk Retail [Member] Waikiki Beach walk retail. Derivative Instrument [Axis] Derivative Instrument [Axis] Senior notes, net 3.375% Senior Notes 3.375% Senior Unsecured Notes [Member] 3.375% Senior Unsecured Notes Provision for doubtful accounts Accounts Receivable, Allowance for Credit Loss In-place leases Leases, Acquired-in-Place [Member] Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Accumulated depreciation Accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Rental expenses Rental expenses Total rental expenses Cost of Other Property Operating Expense Wells Fargo Bank, N.A. Wells Fargo Bank, N.A. [Member] Wells Fargo Bank, N.A. [Member] Hotel operating Other Cost of Operating Revenue Leases [Abstract] Leases [Abstract] Intangible Asset, Finite-Lived, Acquired [Line Items] Intangible Asset, Finite-Lived, Acquired [Line Items] RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Entity Address, State or Province Entity Address, State or Province Acquisition of real estate Payments to Acquire Commercial Real Estate PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Capital Expenditures Segment Reporting, Long-Lived Asset, Expenditure for Addition Nonvested, beginning balance (in shares) Nonvested, ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Notional Amount Notional amount Derivative, Notional Amount Weighted average shares of common stock outstanding - basic (in shares) Weighted average units outstanding - basic (in shares) Weighted average common shares outstanding—basic (in shares) Weighted Average Number of Shares Outstanding, Basic Secured notes payable, net Secured notes payable, net Secured Debt Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Operating Partnership Units Operating Partnership Units [Member] Operating Partnership Units [Member] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Acquired lease intangible assets Finite-Lived Intangible Asset, off-Market Lease, Favorable, Gross Number of reportable segments Number of Reportable Segments 2030 Lessee, Operating Lease, Liability, to be Paid, Year Four DENOMINATOR Computation Of Basic And Diluted Earnings Per Share Denominator [Abstract] Computation Of Basic And Diluted Earnings Per Share Denominator At The Market Equity Program At The Market Equity Program [Member] At The Market Equity Program [Member] Total real estate, at cost Real Estate Investment Property, at Cost Interest and investment income Interest and Other Income Office Total Office Office Segment [Member] Office Segment. 6.150% Senior Notes 6.150% Senior Unsecured Notes [Member] 6.150% Senior Unsecured Notes Property revenue Revenue from Contract with Customer, Including Assessed Tax Other intangible assets, net of accumulated amortization of $2,574 and $2,361, respectively Other Finite-Lived Intangible Assets, Gross Provision for uncollectible rental income Provision for uncollectible rental income Net Investment in Lease, Credit Loss Expense (Reversal) Reclassified within twelve months Cash Flow Hedge Gain (Loss) to be Reclassified within 12 Months Entity Address, City or Town Entity Address, City or Town Summary of Supplement Disclosures Related to Consolidated Statements of Cash Flows Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Total lease cost (income) Lease Income (Cost) Lease Income (Cost) Partial debt repayment, minimum percentage of principal Debt Instrument, Partial Repayment, Minimum Percentage of Principal Debt Instrument, Partial Repayment, Minimum Percentage of Principal Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Maximum secured leverage ratio on revolving credit facility Maximum Secured Leverage Ratio On Revolving Credit Facility Maximum Secured Leverage Ratio On Revolving Credit Facility Summary of Dividends Declared and Paid on Shares of Common Stock and Noncontrolling Common Units Dividends Declared And Paid On Shares Of Common Stock And Noncontrolling Common Units Table [Table Text Block] Dividends declared and paid on shares of common stock and noncontrolling common units. Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Basis of Accounting Basis of Accounting, Policy [Policy Text Block] Maximum secured debt ratio Debt Instrument, Covenants, Maximum Secured Debt Ratio Debt Instrument, Covenants, Maximum Secured Debt Ratio Acquired lease intangible assets, net Acquired lease intangible assets, net Intangible Asset, Finite-Lived, after Accumulated Amortization Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS Net Income (Loss) Available to Common Stockholders, Basic Sublease income Sublease Income Level 2 Fair Value, Inputs, Level 2 [Member] Accumulated amortization Other intangible assets accumulated amortization Intangible Asset, Finite-Lived, Accumulated Amortization Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Revolving credit facility borrowing limit Line of Credit Facility, Maximum Borrowing Capacity Leasing commissions Leasing commissions Increase (Decrease) in Lease Acquisition Costs Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] 2029 Lessor, Operating Lease, Payment to be Received, Year Three Maximum proportion of hotel's fiscal year gross revenues paid for aggregate yearly management fee Maximum Percentage Of Hotels Fiscal Year Gross Revenues Paid For Aggregate Yearly Management Fee Maximum percentage of hotels fiscal year gross revenues paid for aggregate yearly Management fee. Revenues Revenue Benchmark [Member] Percentage rent Lease Rental Income, Percent Rent Lease Rental Income, Percent Rent Recognition of straight-line rents Straight Line Rent Maximum leverage ratio of revolving credit facility Line Of Credit Facility Maximum Leverage Percentage Maximum leverage percentage of revolving credit facility. Issuance of restricted stock (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Concentration Risk Type [Axis] Concentration Risk Type [Axis] NUMERATOR Computation Of Basic And Diluted Earnings Per Share Numerator [Abstract] Computation Of Basic And Diluted Earnings Per Share Numerator Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Term SOFR Screen Rate Term Screen Secured Overnight Financing Rate (SOFR) [Member] Term Screen Secured Overnight Financing Rate (SOFR) Noncontrolling Interests - Unitholders in the Operating Partnership Noncontrolling Interest [Member] Summary of Net Real Estate and Secured Note Payable Balances by Segments Net Real Estate And Secured Note Payable Balances By Segment Table [Table Text Block] Tabular disclosure of the net real estate and secured note payable balances by segment. Use of Estimates Use of Estimates, Policy [Policy Text Block] Related Party, Type [Axis] Related and Nonrelated Parties [Axis] Unsecured term loan, net Unsecured Notes Payable Unsecured Debt [Member] Interest rate swap asset Fair Value Interest Rate Derivative Assets, at Fair Value Repayment of unsecured line of credit Repayments of Lines of Credit Total Secured Notes Payable Outstanding Long-Term Debt Number of calendar months termination fee is based Calendar Months Calendar months. Proceeds from debt, net of issuance costs Proceeds from Debt, Net of Issuance Costs Summary of Current Annual Payment Under Operating Leases Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Document Period End Date Document Period End Date Note offering percent Debt Instrument, Face Issuance Percent Debt Instrument, Face Issuance Percent Changes in operating assets and liabilities Changes in operating assets and liabilities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] General partner's capital, 61,402,515 and 61,390,936 units issued and outstanding as of September 30, 2026 and December 31, 2025, respectively General Partners' Capital Account Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Minimum fixed charge coverage ratio covenant threshold Minimum Fixed Charge Coverage Ratio On Revolving Credit Facility Minimum Fixed Charge Coverage Ratio On Revolving Credit Facility Face amount of debt Debt Instrument, Face Amount Gain on sale of real estate Gain on sale of real estate Gain (Loss) on Sale of Properties 2028 Lessee, Operating Lease, Liability, to be Paid, Year Two EARNINGS PER UNIT - BASIC Earnings Per Share, Basic [Abstract] Security Exchange Name Security Exchange Name Accounts payable and accrued liabilities for construction in progress Construction in Progress Expenditures Incurred but Not yet Paid Effective interest rate Debt Instrument, Interest Rate, Effective Percentage LEASES Lessor, Operating Leases [Text Block] Repairs and maintenance Cost of Property Repairs and Maintenance Stock-based compensation Partners' Capital Account, Unit-Based Payment Arrangement, Amount Rental operating Direct Costs Of Leased Property, Lessor, Expense Direct Costs Of Leased Property, Lessor, Expense Deferred compensation liability Liabilities, Fair Value Disclosure Accumulated other comprehensive (loss) income Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Number of interest rate agreements Number of Interest Rate Derivatives Held Segment Information Segment Reporting, Policy [Policy Text Block] Summary of Properties Owned Schedule of Real Estate Properties [Table Text Block] Name Outstanding Recovery, Individual Name EARNINGS PER COMMON SHARE Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Minimum interest coverage ratio covenant threshold Minimum Unsecured Interest Coverage Ratio Minimum Unsecured Interest Coverage Ratio Total liabilities Liabilities Trading Symbol Trading Symbol Partner Type [Axis] Partner Type [Axis] Geographical [Domain] Geographical [Domain] Summary of Interest Rate Swap Terms Schedule of Interest Rate Derivatives [Table Text Block] Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] Purchase Commitment, Excluding Long-term Commitment [Axis] Purchase Commitment, Excluding Long-Term Commitment [Axis] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] DISTRIBUTIONS PER UNIT (in dollars per share) Distributions Per Limited Partnership and General Partnership Unit, Outstanding, Basic Amortization of debt issuance costs and debt discounts Amortization of debt issuance costs and debt discounts Amortization of Debt Issuance Costs and Discounts Fixed interest rate on derivative Derivative, Fixed Interest Rate Retail Total Retail Retail Segment [Member] Retail Segment. 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Hedging Relationship [Axis] Hedging Relationship [Axis] LIABILITIES: LIABILITIES: Liabilities [Abstract] Office Tenant Office Tenant [Member] Office Tenant Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Limited partners' capital, units outstanding (in shares) Limited Partners' Capital Account, Units Outstanding Total equity Beginning balance Ending balance Equity, Including Portion Attributable to Noncontrolling Interest Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Repayment of unsecured notes payable Repayments of Notes Payable Other liabilities Other Liabilities Summary of Principal Components of Rental Expenses Components Of Rental Expense Table [Table Text Block] Components of rental expense. Unsecured notes payable, net Unsecured notes payable, net Unsecured Debt Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Apartment Building Apartment Building [Member] Other Income and Expenses [Abstract] Other Income and Expenses [Abstract] Payment for management fee Property Management Fee, Monthly Fee Property Management Fee, Monthly Fee Common stock, shares authorized (in shares) Common Stock, Shares Authorized Net real estate Net Real Estate Real Estate Investment Property, Net Straight-line rent liability Deferred Rent Credit Exercise Price Award Exercise Price INVESTING ACTIVITIES INVESTING ACTIVITIES Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Segment Reporting [Line Items] Segment Reporting [Line Items] Deferred rent revenue and amortization of lease intangibles Deferred rent revenue and amortization of lease intangibles Deferred Rent Revenue And Amortization Of Lease Intangibles The increase (decrease) during the reporting period in the amount due that is the result of the cumulative difference between actual rent due and rental income recognized on a straight-line basis. Also includes the amortization of lease intangibles. Document Quarterly Report Document Quarterly Report 2027 Lessor, Operating Lease, Payment to be Received, Year One Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments [Domain] Segments [Domain] Interest Rate Swap Interest Rate Swap [Member] Noncash compensation expense Restricted Stock or Unit Expense Southern California Southern California [Member] Southern California [Member] Net income attributable to unitholders in the Operating Partnership Less: Net income attributable to unitholders in the Operating Partnership Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable Net income attributable to restricted shares Net income attributable to restricted shares Less: Net income attributable to restricted shares Net Income Attributable To Restricted Share Net income attributable to restricted share. Accounts receivable, net Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss Proportion of hotel occupancy gross revenue paid for franchise royalty fee Percentage Of Hotel Occupancy Gross Revenue Paid For Franchise Royalty Fee Percentage of hotel occupancy gross revenue paid for franchise royalty fee. DEBT Debt Disclosure [Text Block] Schedule of Capital Units [Table] Equity, Capital Unit or Share [Table] Weighted average unvested shares outstanding (in shares) Weighted Average Unvested Participating Securities Outstanding Weighted average unvested participating securities outstanding. Management fees Management Fee Expense Debt issuance costs on line of credit, net of accumulated amortization of $3,223 and $2,591, respectively Debt issuance costs, net of accumulated amortization of $791 and $723, respectively Debt discount and issuance costs, net of accumulated amortization of $10,366 and $8,720, respectively Debt issuance costs Debt Issuance Costs, Net Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Total interest costs incurred Interest Costs Incurred Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Equity [Line Items] Equity [Line Items] Equity [Line Items] Secured notes payable, net Secured Debt [Member] Real estate taxes Real estate taxes Real Estate Tax Expense Total operating expenses Costs and Expenses Adoption Date Trading Arrangement Adoption Date Number of sales agents Number Of Sales Agents Number Of Sales Agents Summary of Principal Components of Other Income, Net Schedule of Other Nonoperating Income (Expense) [Table Text Block] Other Other Real Estate Rental Revenue Other real estate rental revenue. Stated interest rate Stated Interest Rate Debt Instrument, Interest Rate, Stated Percentage Counterparty Name [Domain] Counterparty Name [Domain] Total American Assets Trust, Inc. stockholders’ equity Equity, Attributable to Parent American Assets, Inc. American Assets, Inc. [Member] American Assets, Inc. [Member] Real Estate [Domain] Real Estate [Domain] Accrued leasing commissions Increase (Decrease) Accrued Leasing Commissions Change in accrued leasing commissions ASSETS ASSETS Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Other Liabilities Disclosure [Abstract] Other Liabilities Disclosure [Abstract] Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Lease liability Present value of lease liability Operating Lease, Liability Insider Trading Policies and Procedures [Line Items] Other property income Other property income Other Operating Income Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Interest expense, net Interest expense, net Interest expense, net Interest Income (Expense), Nonoperating COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Rental income Rental income Total rental income Operating Lease, Lease Income Construction in progress Construction in progress Construction in Progress, Gross Antidilutive securities excluded from computation of EPS (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Number of operating segments Number of Operating Segments Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Hawaii excise tax Excise and Sales Taxes Entity Central Index Key Entity Central Index Key Additional paid-in capital Additional Paid in Capital, Common Stock All Adjustments to Compensation All Adjustments to Compensation [Member] Equity [Abstract] Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Income Statement [Abstract] Income Statement [Abstract] American Assets Trust, Inc. stockholders’ equity Equity, Attributable to Parent [Abstract] Document Transition Report Document Transition Report Ownership [Axis] Ownership [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Thereafter Lessor, Operating Lease, Payment To Be Received, After Year Four Lessor, Operating Lease, Payment To Be Received, After Year Four Designated as Hedging Instrument Designated as Hedging Instrument [Member] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Intangible Asset, Finite-Lived, Acquired [Table] Intangible Asset, Finite-Lived, Acquired [Table] Variable rate Debt Instrument, Basis Spread on Variable Rate Interest capitalized Interest Costs Capitalized Adjustment Lessor, Lease, Description [Line Items] Lessor, Lease, Description [Line Items] City Area Code City Area Code Variable Rate [Domain] Variable Rate [Domain] Marketing Marketing Expense Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] All Individuals All Individuals [Member] Accumulated accretion Below Market Lease, Accumulated Amortization Dividends paid to common stock and unitholders Distributions Payments of Dividends Name Forgone Recovery, Individual Name American Assets Trust, L.P. American Assets Trust, L.P. [Member] American Assets Trust, L.P. [Member] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Weighted Average Grant Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Make-whole payment Make Whole Payment for Debt Extinguishment Make Whole Payment for Debt Extinguishment ACQUIRED IN-PLACE LEASES AND ABOVE/BELOW MARKET LEASES Intangible Asset [Text Block] Distributions Partners' Capital Account, Distributions Statement [Line Items] Statement [Line Items] TOTAL ASSETS Assets Entity [Domain] Entity [Domain] Term Loan A Term Loan A [Member] Term Loan A [Member] Partner Capital Components [Axis] Partner Capital Components [Axis] Total capital Beginning partners' capital account Ending partners' capital account Partners' Capital Change in other assets Change in other assets Increase (Decrease) in Other Operating Assets Common shares issued (in shares) Stock Issued During Period, Shares, New Issues PEO PEO [Member] Summary of Principal Components of Rental Income Components Of Rental Income Table [Table Text Block] Components of rental income. Measurement Basis [Axis] Measurement Basis [Axis] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Fair Value Inputs Disclosures Fair Value Measurement Inputs and Valuation Techniques [Line Items] Granted (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Accumulated Dividends in Excess of Net Income Retained Earnings [Member] Revolving Loan Revolving Credit Facility [Member] Forfeited (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Fair Value Measurement Fair Value Measurement, Policy [Policy Text Block] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Summary of Carrying Amount and Fair Value of Financial Instruments Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Debt issuance costs Debt issuance costs Payments of Debt Issuance Costs Earnings per common share, diluted (in dollars per share) Earnings per unit, diluted (in dollars per share) Earnings Per Share, Diluted Entity Current Reporting Status Entity Current Reporting Status Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Cash Flow Hedging Cash Flow Hedging [Member] Intangible Asset, Finite-Lived [Line Items] Intangible Asset, Finite-Lived [Line Items] Ownership [Domain] Ownership [Domain] Hotel revenue Revenue from Contract with Customer, Excluding Assessed Tax FINANCING ACTIVITIES FINANCING ACTIVITIES Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Business and Organization Business And Organization, Policy [Policy Text Block] Business and organization. Other liabilities and deferred credits Other liabilities and deferred credits Total other liabilities and deferred credits, net Deferred Credits and Other Liabilities Interest rate swap asset Derivative Asset Intangible Asset, Finite-Lived, Class [Axis] Intangible Asset, Finite-Lived, Class [Axis] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Comprehensive income attributable to non-controlling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Fair Value Estimate of Fair Value Measurement [Member] Derivative Asset, Statement of Financial Position [Extensible Enumeration] Derivative Asset, Statement of Financial Position [Extensible Enumeration] Weighted-average discount rate - operating leases Operating Lease, Weighted Average Discount Rate, Percent Senior Guaranteed Notes, Series E Senior Guaranteed Notes, Series E [Member] Senior Guaranteed Notes, Series E [Member] Segment Reporting Segment Reporting [Table] Term of lease Lessor, Operating Lease, Term of Contract Schedule of Related Party Transactions, by Related Party Related Party Transaction [Table] Sale of Stock [Axis] Sale of Stock [Axis] Summary of Lease Costs Under Operating Leases and Supplemental Cash Flow Information of Leases Lease, Cost [Table Text Block] Gain on derivatives Derivative, Gain on Derivative Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] OPERATING INCOME Operating Income (Loss) Federal Funds Rate Federal Funds Rate [Member] Interest based on Federal Funds Rate. Current Fiscal Year End Date Current Fiscal Year End Date Limited partners' capital, units issued (in shares) Limited Partners' Capital Account, Units Issued Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount PARTNERS' CAPITAL OF AMERICAN ASSETS TRUST, L.P. Partners' Capital Notes Disclosure [Text Block] Investment in WBW CHP LLC, in percentage Percentage Of Investment In Related Party Percentage of investment in related party. Termination payment Loss on Contract Termination for Default Dividends declared and paid Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] DIVIDENDS DECLARED PER COMMON SHARE (in USD per share) Amount per Share/Unit (in dollars per unit) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Common stock, shares issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Property expense Property Expenses Property expenses. Operating cash flow information: Cash Flow, Operating Activities, Lessee [Abstract] Entity Information [Line Items] Entity Information [Line Items] OTHER ASSETS, NET Other Assets Disclosure [Text Block] Increase (Decrease) in Partners' Capital [Roll Forward] Increase (Decrease) in Partners' Capital [Roll Forward] Noncontrolling common units (in shares) Shares Held By Minority Interest In Operating Partnerships Shares held by minority interest in Operating partnerships. Equity Components [Axis] Equity Components [Axis] Change in accounts receivable Change in accounts receivable Increase (Decrease) in Accounts Receivable Related Party Related Party [Member] Entity Interactive Data Current Entity Interactive Data Current Variable Rate [Axis] Variable Rate [Axis] Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Deferred compensation Deferred Compensation Liability, Current and Noncurrent Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Limited Partners Limited Partners' Capital Limited Partner [Member] Conversion of operating partnership units (in shares) Stock Issued During Period, Shares, Conversion of Units Debt issuance costs, net, revolving credit facility Debt Issuance Costs, Line of Credit Arrangements, Net Senior Guaranteed Notes, Series G Senior Guaranteed Notes, Series G [Member] Senior Guaranteed Notes, Series G Entity Small Business Entity Small Business Comprehensive income attributable to American Assets Trust, Inc. Comprehensive Income (Loss), Net of Tax, Attributable to Parent 2029 Lessee, Operating Lease, Liability, to be Paid, Year Three Termination Date Trading Arrangement Termination Date Beginning partners' capital account (in shares) Ending partners' capital account (in shares) Partners' Capital Account, Units Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Loss on derivatives Derivative, Loss on Derivative Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Proportion of hotel occupancy gross revenue paid for program fee Percentage Of Hotel Occupancy Gross Revenue Paid For Program Fee Percentage of hotel occupancy gross revenue paid for program fee. Remaining capacity available for issuance Remaining Capacity To Issue Remaining $ Capacity Of Shares To Issue Leasing commissions accumulative amortization Deferred Initial Direct Cost, Lease, Accumulated Amortization Document Type Document Type Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Purchase Commitment, Excluding Long-term Commitment [Domain] Purchase Commitment, Excluding Long-Term Commitment [Domain] Fair Value as of Grant Date Award Grant Date Fair Value SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies [Text Block] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Change in security deposits payable Change in security deposits payable Increase (Decrease) In Security Deposits Payable Increase (Decrease) In Security Deposits Payable Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Deferred tax liability Deferred Tax Liabilities, Gross Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Forfeiture of restricted units (in shares) Partners' Capital Account, Restricted Units Forfeiture Partners' Capital Account, Restricted Units Forfeiture Commitments and contingencies (Note 11) Commitments and contingencies (Note 11) Commitments and Contingencies Total revenue Revenues Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Change in accounts payable and accrued expenses Change in accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Counterparty Name [Axis] Counterparty Name [Axis] EXPENSES: EXPENSES: Operating Costs and Expenses [Abstract] LIABILITIES AND EQUITY LIABILITIES AND CAPITAL Liabilities and Equity [Abstract] Intangible Asset, Finite-Lived, Class [Domain] Intangible Asset, Finite-Lived, Class [Domain] 2030 Lessor, Operating Lease, Payment to be Received, Year Four Summary of Financial Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount 2026 (three months ending December 31, 2026) Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Reclassification of amortization of forward-starting swaps included in interest expense Reclassification of amortization of forward-starting swaps included in interest expense Reclassification of amortization of forward-starting swaps included in interest expense Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Recognition of amortization of above and below market leases Amortization of above and below Market Leases Percentage of ownership interests classified as noncontrolling Subsidiary, Ownership Percentage, Noncontrolling Owner Accounts payable and accrued expenses Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities PEO Name PEO Name Geographical [Axis] Geographical [Axis] Total Lessor, Operating Lease, Payment to be Received Years of contract Years Of Contract Years of contract. Cash paid for income taxes Income Tax Paid, before Refund Received Weighted average interest rate Line of Credit Facility, Interest Rate During Period Mixed-use Total Mixed-Use Mixed Use Segment [Member] Mixed Use Segment [Member] Other assets, net Other assets, net Total other assets, net Other Assets Bank of America, N.A. Bank of America, N.A. [Member] Bank of America, N.A. Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Derivative Instruments and Hedging Activities Disclosures [Table] Derivative Instruments and Hedging Activities Disclosures [Table] Legal Entity [Axis] Legal Entity [Axis] Interest Rate Swap, 1/5/2027 Interest Rate Swap, 1/5/2027 [Member] Interest Rate Swap, 1/5/2027 Other comprehensive loss - change in value of interest rate swaps Other comprehensive loss - change in value of interest rate swaps Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Secured Notes Payable Notes Payable Revenue Recognition and Accounts Receivable Revenue [Policy Text Block] Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Schedule of Finite-Lived Intangible Assets [Table] Intangible Asset, Finite-Lived [Table] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Base Rate Base Rate [Member] Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Wbw Hotel Lessee Llc Wbw Hotel Lessee Llc [Member] WBW Hotel Lessee LLC. Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Debt Instrument [Axis] Debt Instrument [Axis] Stock-based compensation expense Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Maximum unsecured leverage ratio Maximum Unsecured Leverage Ratio Maximum Unsecured Leverage Ratio Limited partners' capital, 16,181,537 and 16,181,537 units issued and outstanding as of September 30, 2026 and December 31, 2025, respectively Limited Partners' Capital Account Summary of Notes Payable Outstanding Schedule of Debt [Table Text Block] Incurred expenses Related Party Transaction, Amounts of Transaction Customer [Domain] Customer [Domain] Properties held for development Real Estate Properties Held For Development The number of real estate properties held for development. LEASES Lessee, Operating Leases [Text Block] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Earnings per common share, basic (in dollars per share) Earnings per unit, basic (in dollars per share) Earnings Per Share, Basic Prepaid rent and deferred revenue Deferred Revenue Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] COMPONENTS OF RENTAL INCOME AND EXPENSE Components Of Rental Income And Expense [Text Block] The entire disclosure of the principle components of rental income and/or rental expense recognized for the period. Award Type [Axis] Award Type [Axis] 2026 (three months ending December 31, 2026) Lessor, Operating Lease, Payment to be Received, Remainder of Fiscal Year Minimum maintenance of total unencumbered assets Debt Instrument, Covenants, Minimum Maintenance Of Total Unencumbered Assets Debt Instrument, Covenants, Minimum Maintenance Of Total Unencumbered Assets Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Accumulated dividends in excess of net income Retained Earnings (Accumulated Deficit) Rental Income [Line Items] Rental Income [Line Items] Rental Income [Line Items] CAPITAL: Partners' Capital [Abstract] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common Shares Common Stock [Member] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Operating lease cost Operating Lease, Cost Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover page. Cover [Abstract] Common unit conversion ratio Partners Capital Redemption & Conversion Ratio Partners Capital Redemption & Conversion Ratio Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Proportion of total revenue provided by retail or office tenants Concentration Risk, Percentage Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Commitment And Contingencies [Line Items] Commitment And Contingencies [Line Items] Commitment And Contingencies [Line Items] Equity Awards Adjustments Equity Awards Adjustments [Member] Summary of Other Liabilities and Deferred Credits Other Liabilities And Deferred Credits Table [Table Text Block] Tabular disclosure of other liabilities and deferred credits not separately disclosed on the balance sheet. Hedging Relationship [Domain] Hedging Relationship [Domain] Security deposits payable Security deposits payable Security Deposit Liability TOTAL LIABILITIES AND EQUITY Liabilities and Equity Employee Stock Option Share-Based Payment Arrangement, Option [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Noncontrolling interests Equity, Attributable to Noncontrolling Interest Summary of Minimum Future Rentals from Noncancelable Operating Leases Lessor, Operating Lease, Payment to be Received, Maturity [Table Text Block] Segments [Axis] Segments [Axis] Termination notice period Termination Notice Period Termination Notice Period Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Related Party, Type [Domain] Related and Nonrelated Parties [Domain] Tabular List, Table Tabular List [Table Text Block] General partners' capital, units outstanding (in shares) General Partners' Capital Account, Units Outstanding Other income, net Other income, net Total other income Other income, net Other Nonoperating Income (Expense) Name Awards Close in Time to MNPI Disclosures, Individual Name EQUITY: Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period General and administrative General and administrative General and administrative General and Administrative Expense Other noncash interest expense, net Other noncash interest expense, net Other Non-cash Interest Expense Other Non-cash Interest Expense Fair value rates Debt Instrument, Measurement Input Adjustment to Compensation: Adjustment to Compensation [Axis] Office, retail, multifamily, and mixed-use operating properties Number of Real Estate Properties Summary of Acquired Lease Intangibles and Leasing Costs Included in Other Assets and Other Liabilities and Deferred Credits Business Combination, Intangible Asset, Acquired, Finite-Lived [Table Text Block] Senior Guaranteed Notes, Series A Senior Guaranteed Notes, Series A [Member] aat_SeniorGuaranteedNotes,SeriesA Hedging Designation [Domain] Hedging Designation [Domain] Lease rental income Lease Rental Income Lease Rental Income Multifamily Total Multifamily Multifamily Segment [Member] Multifamily Segment [Member] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Cash paid for interest, net of amounts capitalized Interest Paid, Excluding Capitalized Interest, Operating Activity Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Hedging Designation [Axis] Hedging Designation [Axis] Below market leases Below Market Lease, Gross Maximum aggregate debt ratio Debt Instrument, Covenants, Maximum Aggregate Debt Ratio Debt Instrument, Covenants, Maximum Aggregate Debt Ratio Credit Facility [Axis] Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Name Measure Name INCOME TAXES Income Tax Disclosure [Text Block] Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Other, net Other, net Other Noncash Income (Expense) Aggregate offering price of common share Aggregate Offering Price Of Common Share Maximum aggregate offering price of common shares. Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Additional Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category AAI Aviation Inc AAI Aviation, Inc. (AAIA) [Member] AAI Aviation, Inc. (AAIA) General partners' capital, units issued (in shares) General Partners' Capital Account, Units Issued Name Trading Arrangement, Individual Name Unrecognized compensation expense Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Cash and cash equivalents Cash and cash equivalents Cash and Cash Equivalent General Partners General Partner's Capital General Partner [Member] Rent Operating Lease, Expense Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Company Selected Measure Amount Company Selected Measure Amount Summary of Segment Activity Segment Reporting, Reconciliation of Profit (Loss) by Segment to Consolidated [Table Text Block] Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization Senior Guaranteed Notes, Series D Senior Guaranteed Notes, Series D [Member] Senior Guaranteed Notes, Series D [Member] Lease incentives, net of accumulated amortization of $1,326 and $1,239, respectively Incentive to Lessee SOFR Secured Overnight Financing Rate (SOFR) [Member] Number of employees Entity Number of Employees Acquired lease intangible liabilities, net Below Market Lease, Net Entity Address, Address Line Two Entity Address, Address Line Two Held for development Held for development Land Available for Development NET INCOME Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Real estate, at cost Real Estate [Abstract] Weighted-average remaining lease term - operating leases (in years) Operating Lease, Weighted Average Remaining Lease Term Proceeds from sale of real estate, net of selling costs Proceeds from Sale, Real Estate, Held-for-Investment Non-PEO NEO Non-PEO NEO [Member] Unsecured senior guaranteed notes, net Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Second Amended and Restated Credit Facility Second Amended and Restated Credit Facility [Member] Second Amended and Restated Credit Facility [Member] Vested (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Income tax expense Income tax expense Income Tax Expense (Benefit) Leasing commissions, net of accumulated amortization of $58,918 and $56,094, respectively Deferred Initial Direct Cost, Lease, after Accumulated Amortization OTHER INCOME Other Income and Other Expense Disclosure [Text Block] Operating real estate Operating real estate Rental Properties Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to reconcile net income to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Noncash Item [Abstract] Forfeiture of restricted stock (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Forfeited Customer Concentration Risk Customer Concentration Risk [Member] Award Timing Method Award Timing Method [Text Block] Basis of Presentation Consolidation, Policy [Policy Text Block] Net decrease in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Thereafter Lessee, Operating Lease, Liability, To Be Paid, After Year Four Lessee, Operating Lease, Liability, To Be Paid, After Year Four Property management fee Property Management Fee, Percent Fee Senior Guaranteed Notes, Series C Senior Guaranteed Notes, Series C [Member] Senior Guaranteed Notes, Series C [Member] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Acquired below market leases, net Off-Market Lease, Unfavorable Deferred tax asset Deferred Tax Assets, Net of Valuation Allowance 2028 Lessor, Operating Lease, Payment to be Received, Year Two Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Summary of Reconciliation of Segment Profit to Net Income Attributable to Stockholders Reconciliation Of Segment Profit To Net Income Attributable To Stockholders Table [Table Text Block] Reconciliation of segment profit to net income attributable to stockholders. Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Statement [Table] Statement [Table] Treasury Lock Treasury Lock [Member] Above market leases Above Market Leases [Member] Restatement Determination Date: Restatement Determination Date [Axis] WBW CHP LLC WBW CHP LLC [Member] WBW CHP LLC Issuance of restricted stock Stock Issued During Period, Value, Restricted Stock Award, Gross Series B Notes Senior Guaranteed Notes, Series B [Member] Senior Guaranteed Notes, Series B Derivative Instruments and Hedging Activities Disclosures [Line Items] Derivative Instruments and Hedging Activities Disclosures [Line Items] Net income attributable to American Assets Trust, Inc. common stockholders—basic Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Average annual rent Operating Lease, Average Annual Rent Operating Lease, Average Annual Rent Summary of Components of Other Assets Schedule of Other Assets [Table Text Block] Minimum debt service ratio Debt Instrument, Covenants, Minimum Debt Service Ratio Debt Instrument, Covenants, Minimum Debt Service Ratio Plus: Net income attributable to unitholders in the Operating Partnership Minority Interest In Continuing Operations Income Loss Operating Partnerships - Diluted Minority Interest In Continuing Operations Income Loss Operating Partnerships - Diluted REVENUE: REVENUE: Revenues [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]